D. c.-a. c. inverters



Oct. 7, 1958 H. B'HM ETAL 2,855,474

D. C.-A. c. INVERTERS Filed July 6, 1956 United States Patent D. C.-A.C. INVERTERS Hellmuth Biihm, Berlin-Charlottenburg, and Gerhard Bettin,Berlin-Grunewald, Germany, assignors to Licentia Patent-Verwaltungs G.m. b. H., Hamburg, Germany Application July 6, 1956, Serial No. 596,201

Claims priority, application Germany July 6, 1955 3 Claims. (Cl. 200-32)This invention relates to apparatus for the inverted conversion ofdirect electric current to alternating electric current. More inparticular, this invention relates to the driving means for impellingthe centrifuge in a turbo-liquid jet D. C.-A. C. converter.

It is the object of this invention to provide for a driving arrangementfor impelling the centrifuge in a turbo-type liquid jet D. C.-A. C.inverted converter that assures in a simple and uncomplicated manner anexact, uniform and non-excentric rotation of the centrifugal cone of thecentrifuge.

It is known in the art to install the centrifugal cone of turbo liquidjet inverters in a comparatively low position in the casing of suchinverters. For this reason the driving shaft extending downwardly fromthe motor installed in the upper part of the casing, is considerablyelongated.

The disadvantage of this arrangement, however, is that the shaft mustrotate with great accuracy in order to prevent the centrifugal cone fromexecuting eccentric movements.

This disadvantage has been avoided by providing separate and independentbearings for the driving shaft on the one hand and the centrifugal coneshaft on the other hand. However, the advantage of this construction iscompensated by the concurring drawback of its being relativelycomplicated and consequently expensive.

These drawbacks are avoided and the objects of my invention achieved byproviding a drive for inverted converters which comprises the feature ofmounting the bearings for the centrifugal cone shaft on the body of thecentrifugal cone proper and by coupling the centrifugal cone shaft withthe driving shaft.

The invention will be more fully understood and its distinctive featuresand advantages over the known art will be more fully appreciated by adetailed description of the accompanying drawing in which:

The single figure represents a partially sectional front view of apreferred embodiment of the apparatus according to our invention, fromwhich part of the casing has been removed.

More in particular, the casing 1 which is evacuated through stud 1aencloses a plurality of circularly positioned contacts 2 and a motor 3.The short stump of driving shaft 4 extends from the motor 3 in downwarddirection. This shaft 4 is connected in a manner to be describedpresently with the shaft 5 of the centrifugal cone 6. The centrifugalcone 6 bears at its lower end two jet arms 7 extending in upwarddirection and forming an acute angle with the longitudinal center lineof cone 6. The jet arms 7 raise the liquid 8-preferably mercury from thetapering bottom of the casing 1 forming a small tank and jet the liquidagainst the contacts 2.

In substantially the central horizontal plane of the casiiatented Oct.7, 1958 ing a separating wall 10 separates the motor 3 from thecentrifugal jet device described above. A hollow shank 9 is fastened toand partly inserted into this separating wall and extends in downwarddirection into the lower part of casing 1, and encloses both shaft 4 andshaft 5. At the lower end and inside of this shank 9, bearing means aremounted consisting in the preferred embodiment of the invention shown bythe figure of a retaining or sealing ring 11 and a ball bearing 12. Thestump of the motor shaft 4 and the shaft 5 are joined together by acoupling element 13 which is connected by pegs 14 and 15 both to shaft 4and to shaft 5 so that the parts 13, 14, 15 act as a universal typeconnecting means for connecting the shafts 4 and 5 for rotation inunison with each other. Preferably a distancing sleeve 16 is interposedbetween the bearing 12 and the coupling element 13 in order to preventthe driving shaft from sliding downwardly.

It will be understood that this invention is susceptible to furthermodification and, accordingly, it is desired to comprehend suchmodifications within this invention as may fall within the scope of theappended claims.

What we claim is:

1. A D. C.-A. C. current converter of the mercury jet type, comprising acasing, a horizontal wall therein dividing said easing into an upper anda lower chamber, an electric motor in said upper chamber, a motorshaftextending downwardly into said lower chamber, a centrifuging cone insaid lower chamber, a cone shaft on the lower end of which saidcentrifuging cone is mounted for rotation. therewith, said cone shaftbeing aligned with said motor shaft, universal type connecting means forconnecting said motor shaft with the upper end of said cone shaft forrotation in unison therewith, bearing means comprising a tubular memberextending downwardly from said horizontal wall and enclosing thejunction between said cone shaft and said motor shaft, a single rotaryantifriction bearing mounted inside said tubular member toward the lowerend thereof and supporting said cone shaft near the lower end thereofclose to said centrifuging cone, and a distancing sleeve inside saidtubular member enclosing said cone shaft between said rotary bearing andsaid connecting means and supporting said connecting means and the motorshaft connected thereto on said rotary bearing.

2. A D. C.-A. C. current converter as described in claim 1 wherein saidjunction between said cone shaft and said motor shaft is located nearthe upper end of said tubular member.

3. A D. C.-A. C. current converter as described in claim 1, wherein saiduniversal type connecting means are lo cated entirely within saidtubular member.

References Cited in the file of this patent UNITED STATES PATENTS688,068 Cunningham Dec. 3, 1901 866,289 Luschka Sept. 17, 1907 895,044Rothenstein 1 Aug. 4, 1908 940,069 Rowe Nov. 16, 1909 2,163,507 WolczekJune 20, 1939 2,195,909 Wagner Apr. 2, 1940 2,444,687 Widakowich July 6,1948 2,795,662 Bohm June 11, 1957 FOREIGN PATENTS 334,301 Germany Mar.11, 1921

